Engine stalls when at idle?

Tiny
RIVERMIKERAT
  • EXPERT
Check the fuel pump itself when the problem occurs. Key on, engine off, check fuel pressure. Check the injector relay also. One or the other is suffering an intermittent failure.
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Friday, January 29th, 2021 AT 11:01 AM (Merged)
Tiny
RASMATAZ
  • EXPERT
Clean out the idle air control valve and EGR valve to include checking the fuel pressure if its within specs
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Friday, January 29th, 2021 AT 11:01 AM (Merged)
Tiny
JAGFIX
  • MEMBER
I visually inspected the EGR valve and didn't notice any faults. I need to check it with a vacuum tester I suppose. Not sure where the injector relay is located.
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Friday, January 29th, 2021 AT 11:01 AM (Merged)
Tiny
RIVERMIKERAT
  • EXPERT
Should be in the underhood relay box just aft of the battery.
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Friday, January 29th, 2021 AT 11:01 AM (Merged)
Tiny
JAGFIX
  • MEMBER
I do not have a relay box under the hood. There are 2 relays located on the firewall and a relay box that houses the fuel pump relay in the cabin below the center console. My manual doesn't show a injector relay. Any suggestions?
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Friday, January 29th, 2021 AT 11:01 AM (Merged)
Tiny
RIVERMIKERAT
  • EXPERT
Check to see if the injector is pulsing. I have attached a schematic that shows where the injector receives its signal from. Upper right corner.
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Friday, January 29th, 2021 AT 11:01 AM (Merged)
Tiny
JAGFIX
  • MEMBER
Thank you for the schematic. It is hard to view and it appears to be different than my vehicle wires. I noticed the schematic is for a VIN W. I have the TBI VIN Z.
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Friday, January 29th, 2021 AT 11:01 AM (Merged)
Tiny
RIVERMIKERAT
  • EXPERT
VIN Z schematic. Slightly different. Click the thumbnail. Then right click the image and select "Save Image As". Then you can view it with any image viewing software you may have, or print it.
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Friday, January 29th, 2021 AT 11:01 AM (Merged)
Tiny
JAGFIX
  • MEMBER
Ok guys. The abouve diagram was too blurry once printed, but thank you anyway. I spent the majority of Sunday messing with this thing with no success. Here it is Monday morning, and it starts right up and stays running. What the heck is going on? Brought it to work so no walking today. I'll see what happens around 5 when I go home. I might do some more checks at lunch time. Any more suggestions please? The IAC was removed and appears to be clean and not stcking. The PCM was removed and no visual problems noticed. There is a red pig tail under the hood to apply battery voltage to, to power up the fuel pump. I hear the pump running with battery voltage being applied to the pig tail. Is it safe to try that while the engine is running and apply the voltage just about when you can tell it's going to stall?
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Friday, January 29th, 2021 AT 11:01 AM (Merged)
Tiny
RASMATAZ
  • EXPERT
You were told to check fuel pressure 2x and I don't see you performing it-the fuel pressure is critical we need to know what it is before we can continue to help you-
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Friday, January 29th, 2021 AT 11:01 AM (Merged)
Tiny
JAGFIX
  • MEMBER
The fuel pressure was about 13psi.
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Friday, January 29th, 2021 AT 11:01 AM (Merged)
Tiny
RASMATAZ
  • EXPERT
How did the EGR valve and ports looks when you open it up? The IACV is clean try replacing it and see what happens
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Friday, January 29th, 2021 AT 11:01 AM (Merged)
Tiny
JAGFIX
  • MEMBER
EGR valve looked good and with vacuum applied the diaphram moves and holds steady so I assume it is good. I guess I can try a IAC valve but I don't like the idea of throwing parts on it like the ignition module which didn't fix it but I guess I don't have a choice at this point. Thanks for the info. I'll keep you posted. At lunch it started right up with no faults again. I bet it won't run when it's time to go home though.
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Friday, January 29th, 2021 AT 11:01 AM (Merged)
Tiny
RASMATAZ
  • EXPERT
Think! Positively were trying our damnest to help you out-Did you clean out the IACV port? Were not here to tell people to throw parts at it till its fixed, if we do we don't belong here-Remember were not there with the vehicle-Good Luck
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Friday, January 29th, 2021 AT 11:01 AM (Merged)
Tiny
JAGFIX
  • MEMBER
I understand. I thank you guys for the help and advice. Just gets very frustrating as you probably understand. Would an IAC valve cause these issues only at start up? Trying to understand what exactly is happening during start up and idle that would cause this mystery to occur. Never stalls when driving it. Reliable while it's actually running, just getting it to that point is difficult sometimes. Really weird how it acts up sometimes for a few starts, then somehow fixes itself, then will drive fine for 3 - 5 days with no problems then all of a sudden the next morning it won't start again. Freaky?
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Friday, January 29th, 2021 AT 11:01 AM (Merged)
Tiny
NOVACLONE
  • MEMBER
  • 1994 CHEVROLET S-10
Engine Performance problem
1994 Chevy S-10 6 cyl Four Wheel Drive Automatic

When I try to start my 1994 s-10 Blazer, 4.3 auto, it will only start when the gas pedal is held down a little bit, and when you release the gas pedal, it will not idle and dies. It will drive fine until you have to let up on the gas pedal and then it will die. I actually swapped out everything that had a wire running to the intake area with another running s-10 that I own and nothing seem to change the starting issue. All vacuum lines are hooked up. However when I pulled the off the map sensor and left it out by accident, it started right up and ran fine, Now what?
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Friday, January 29th, 2021 AT 11:01 AM (Merged)
Tiny
LEGITIMATE007
  • EXPERT
Replace the map sensor and see how it does. That is more than likely the problem since you unhooked it and it ran fine.
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Friday, January 29th, 2021 AT 11:01 AM (Merged)
Tiny
RIVERMIKERAT
  • EXPERT
That 13PSI fuel pressure reading concerns me. It should be much higher, like between 30 and 50PSI. Try checking the fuel pressure over a period of time. When it's acting up and when it's driving nicely. See if it varies and by how much.
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Friday, January 29th, 2021 AT 11:01 AM (Merged)
Tiny
NOVACLONE
  • MEMBER
I have already swapped out the map sensor off of another good running s10 that I own and it did'nt fix it.
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Friday, January 29th, 2021 AT 11:01 AM (Merged)
Tiny
JAGFIX
  • MEMBER
Well, it wouldn't start yesterday after work. Does the same thing as before. Actually it does start but stalls about 5 - 10 seconds later. This is a TBI Z VIN engine. I think the pressure is suppose to be around 13psi.
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Friday, January 29th, 2021 AT 11:01 AM (Merged)

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